Measuring instrument and measuring method for thickness of wafer metal film

Abstract

The invention provides a measuring instrument and a measuring method for the thickness of a wafer metal film, and the measuring method is used for the measuring instrument for the thickness of the wafer metal film. The measuring instrument comprises a bearing disc used for bearing a wafer, and the upper surface of the wafer is covered with a metal film; the eddy current sensor is arranged above the bearing disc and is configured to excite an eddy current magnetic field in the metal film of the wafer by utilizing an eddy current effect and detect the intensity of the eddy current magnetic field so as to generate a corresponding output signal; and the distance measuring sensor is arranged above the bearing disc and is used for measuring the lift-off height from the eddy current sensor to the wafer. The measurement method comprises the following steps: when a to-be-detected wafer is carried by a carrying disc, respectively obtaining a target output signal generated by an eddy current sensor and a target lift-off height measured by a distance measuring sensor; and determining the thickness of the metal film of the wafer to be detected according to the target output signal and the target lift-off height.

Description

[0001] This application is a divisional application of the invention patent application with the application number 202310505303.8 and filed on May 6, 2023. Technical Field

[0002] The present disclosure relates to the field of semiconductor technology, and more particularly to a measuring instrument and method for the thickness of a metal thin film on a wafer, an electronic device, a computer-readable storage medium, and a computer program product. Background Art

[0003] Integrated circuits (ICs) are the core and lifeline of the development of the information technology industry. Integrated circuits are generally formed by successively depositing conductive layers, semiconductor layers, or insulating layers on a silicon wafer. Thus, a thin film formed by a filler layer is deposited on the surface of the wafer. In the manufacturing process, it is necessary to continuously planarize the filler layer until the patterned top surface is exposed to form a conductive path between the raised patterns.

[0004] With the rapid development of semiconductor materials and semiconductor manufacturing processes, there are more and more research solutions for the thickness characteristics of the metal film on the wafer surface. At present, not only reliable semiconductor substrate materials and semiconductor process preparation capabilities are required, but also stable and reliable test tools are needed to accurately judge the morphology of the metal thin film on the wafer surface. However, there is currently no relevant measuring device on the market that can accurately measure the thickness of the metal thin film on the wafer surface.

[0005] The methods described in this section are not necessarily methods that have been previously conceived or adopted. Unless otherwise specified, any method described in this section should not be considered prior art merely because it is included in this section. Similarly, unless otherwise specified, the problems mentioned in this section should not be considered to have been recognized in any prior art. Summary of the Invention

[0006] According to a first aspect of an embodiment of the present disclosure, there is provided a method for measuring the thickness of a metal thin film on a wafer. The measuring method is used for a measuring instrument for the thickness of a metal thin film on a wafer. The measuring instrument includes: a carrier plate for carrying a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier plate and configured to excite an eddy current magnetic field in the metal thin film of the wafer by using the eddy current effect and detect the intensity of the eddy current magnetic field to generate a corresponding output signal; and a ranging sensor disposed above the carrier plate for measuring the lift-off height of the eddy current sensor from the wafer. The measuring method includes: when the carrier plate carries the wafer to be detected, respectively obtaining a target output signal generated by the eddy current sensor and a target lift-off height measured by the ranging sensor; and determining the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height.

[0007] According to a second aspect of the embodiments of the present disclosure, there is provided a measuring instrument for the thickness of a metal thin film on a wafer, including: a carrier plate for carrying the wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier plate and configured to use the eddy current effect to excite an eddy current magnetic field in the metal thin film of the wafer and detect the intensity of the eddy current magnetic field to generate a corresponding output signal; a ranging sensor disposed above the carrier plate for measuring the lift-off height of the eddy current sensor from the wafer; and a processor communicatively connected to the eddy current sensor and the ranging sensor and configured to, when the carrier plate carries the wafer to be detected, respectively obtain the target output signal generated by the eddy current sensor and the target lift-off height measured by the ranging sensor; and determine the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height.

[0008] According to a third aspect of the embodiments of the present disclosure, there is provided an electronic device, including: at least one processor; and at least one memory having a computer program stored thereon, wherein when the computer program is executed by the at least one processor, the at least one processor is caused to execute the above-mentioned method for measuring the thickness of a metal thin film on a wafer.

[0009] According to a fourth aspect of the embodiments of the present disclosure, there is provided a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the processor is caused to execute the above-mentioned method for measuring the thickness of a metal thin film on a wafer.

[0010] According to a fourth aspect of the embodiments of the present disclosure, there is provided a computer program product including a computer program, and when the computer program is executed by a processor, the processor is caused to execute the above-mentioned measuring method.

[0011] According to one or more embodiments of the present disclosure, when measuring the thickness of a metal thin film on a wafer, the influence of the output signal magnitude of the eddy current sensor and the lift-off height on the measurement result is comprehensively considered. Therefore, the thickness value of the metal thin film obtained by using the measuring method of the present disclosure is more accurate than the thickness value determined only by using the output signal of the eddy current sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings exemplarily show embodiments and form a part of the specification, and are used together with the written description of the specification to illustrate the exemplary embodiments. The shown embodiments are for illustrative purposes only and do not limit the scope of the claims. In all the drawings, the same reference numerals refer to the same elements or elements that are similar but not necessarily the same.

[0013] Figure 1 is a schematic structural diagram of a measuring instrument for the thickness of a metal thin film on a wafer according to an embodiment of the present disclosure;

[0014] Figure 2 is a flowchart showing a method for measuring the thickness of a metal thin film on a wafer according to an embodiment of the present disclosure;

[0015] Figure 3 is a flowchart showing a method for measuring the thickness of a metal thin film on a wafer according to an embodiment of the present disclosure;

[0016] Figure 4 is a flowchart showing a method for determining a first mapping relationship according to an embodiment of the present disclosure;

[0017] Figure 5 is a flowchart showing a method for determining a second mapping relationship according to an embodiment of the present disclosure;

[0018] Figure 6 shows a curve relationship diagram of the lift-off height and the corresponding output signal obtained for a sample wafer according to an embodiment of the present disclosure;

[0019] Figure 7 is a flowchart showing a method for obtaining a target output signal and a target lift-off height according to an embodiment of the present disclosure; and

[0020] Figure 8 is a schematic diagram showing a preset path according to an embodiment of the present disclosure;

[0021] Figure 9 is a schematic longitudinal cross-sectional view of a measuring instrument according to an embodiment of the present disclosure;

[0022] Figure 10 shows a schematic diagram of 2D graphical display of the thickness of the metal thin film of the wafer to be detected;

[0023] Figure 11 shows a schematic diagram of 3D graphical display of the thickness of the metal thin film of the wafer to be detected;

[0024] Figure 12 shows an example configuration of an electronic device that can be used to implement the methods described herein. Detailed Description of the Invention

[0025] The present disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the related invention and are not intended to limit the invention. In addition, it should be noted that for the sake of description, only parts related to the related invention are shown in the drawings.

[0026] It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other. Unless otherwise clearly indicated in the context, if the number of elements is not specifically limited, the element may be one or more. In addition, the numbers used for the steps or functional modules in the present disclosure are only used to identify each step or functional module, rather than to limit the execution order of each step or the connection relationship between each functional module.

[0027] In the present disclosure, unless otherwise specified, the terms "first", "second", etc. are used to describe various elements and are not intended to limit the positional relationship, timing relationship or importance relationship of these elements. Such terms are only used to distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of the element, and in certain cases, based on the description of the context, they may also refer to different instances.

[0028] In the present disclosure, the terms used in the description of various examples are only for the purpose of describing specific examples and are not intended to be limiting. Unless otherwise clearly indicated in the context, if the number of elements is not specifically limited, the element may be one or more. In addition, the term "and / or" used in the present disclosure covers any one of the listed items and all possible combinations.

[0029] The specific implementation manners of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0030] According to an embodiment of the present disclosure, a method for measuring the thickness of a wafer metal thin film is first proposed. This measurement method is used for a measuring instrument for the thickness of a wafer metal thin film in the present disclosure. To introduce the measurement method of the embodiment of the present disclosure in more detail, the measuring instrument for the thickness of a wafer metal thin film will be described first.

[0031] Figure 1 FIG. shows a schematic structural diagram of a measuring instrument 100 for the thickness of a wafer metal thin film according to an embodiment of the present disclosure. As Figure 1As shown in the figure, the measuring instrument 100 includes: a carrier plate 30, an eddy current sensor 20, and a ranging sensor 50. The carrier plate 30 is used to carry a wafer, wherein the upper surface of the wafer is covered with a metal thin film. The carrier plate 30 can have an adsorption function and can adsorb the wafer it carries so that the wafer remains stationary relative to the carrier plate 30. The above adsorption function can be realized, for example, by a vacuum adsorption device. The eddy current sensor 20 is arranged above the carrier plate 30 and is configured to use the eddy current effect to excite an eddy current magnetic field in the metal thin film of the wafer and detect the intensity of the eddy current magnetic field to generate a corresponding output signal. As an example, the eddy current sensor 20 can include an excitation coil, an induction coil, a coil skeleton, and a shielding case. The excitation coil is passed through with an alternating current signal of a fixed frequency to generate an alternating magnetic field, and then an induced electromotive force is generated in the metal thin film and the induction coil. There is a coupled electromagnetic induction relationship among the excitation coil, the induction coil, and the metal thin film. The eddy current sensor 20, as the core part of the measuring instrument 100, is mainly used to excite an alternating electromagnetic field in the metal thin film and sense the change in the induced electromotive force generated by the mutual inductance effect caused by metal thin films of different thicknesses. Under the condition that other conditions remain unchanged, there is a one-to-one correspondence between the induced electromotive force and the thickness of the metal thin film. Therefore, the output signal of the eddy current sensor 20 is related to the thickness of the metal thin film. The ranging sensor 50 is arranged above the carrier plate 30 and is used to measure the lift-off height of the eddy current sensor 20 from the wafer. The ranging sensor 50 includes, but is not limited to, a millimeter wave sensor, a laser ranging sensor, an infrared ranging sensor, etc. During the measurement process, the sampling frequency of the ranging sensor 50 is, for example, the same as that of the eddy current sensor 20, so as to output the lift-off height of the eddy current sensor 20 from the wafer in real time.

[0032] Continue to refer to Figure 1 , in some embodiments, the measuring instrument 100 further includes a distance adjustment device 11. Both the eddy current sensor 20 and the ranging sensor 50 are fixed on the distance adjustment device 11, and the distance adjustment device 11 is configured to adjust the lift-off height from the wafer surface. Exemplarily, the above distance adjustment device 11 can include a stepping motor, and the output end of the stepping motor is fixedly connected to the eddy current sensor 20 and the ranging sensor 50 to drive the two to move in the Figure 1 Z direction shown in the figure. In some other embodiments, the above distance adjustment device 11 can further include other driving mechanisms in addition to the stepping motor, as long as the distance adjustment device 11 can drive the eddy current sensor 20 and the ranging sensor 50 to move in the vertical direction. The present disclosure does not limit the specific structure of the distance adjustment device 11.

[0033] Figure 2 The flowchart of the measuring method 200 for the thickness of the metal thin film of the wafer according to the embodiment of the present disclosure is shown.

[0034] As shown in Figure 2 FIG. 2, measurement method 200 includes:

[0035] Step 210, when the carrier plate 30 carries the wafer to be detected, respectively obtain the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50; and

[0036] Step 220, determine the thickness of the metal film of the wafer to be detected according to the target output signal and the target lift-off height.

[0037] In step 210, a tester can place the wafer to be detected on the carrier plate 30, and adjust the positions of the eddy current sensor 20 and the ranging sensor 50 in the space above the carrier plate 30 to reach a preset measurement point. Then obtain the readings of the eddy current sensor 20 and the ranging sensor 50 respectively, that is, the target output signal and the target lift-off height.

[0038] As described above, when other conditions remain unchanged, there is a one-to-one correspondence between the output signal of the eddy current sensor 20 and the thickness of the metal film. In addition, the lift-off height will also affect the resolution of the eddy current sensor 20. Therefore, the output signal of the eddy current sensor 20 is also related to the lift-off height. Therefore, in step 220, the thickness of the metal film of the wafer to be detected can be jointly determined according to both the target output signal and the target lift-off height. In some embodiments, the functional relationship between the thickness of the metal film, the output signal of the eddy current sensor 20, and the lift-off height can be determined in advance, and then the target output signal and the target lift-off height are substituted into the above functional relationship to obtain the thickness of the metal film.

[0039] According to the measurement method 200 of one or more embodiments of the present disclosure, when measuring the thickness of the metal film of the wafer, the influence of the output signal magnitude of the eddy current sensor 20 and the lift-off height on the measurement result is comprehensively considered. Therefore, the thickness value of the metal film obtained by using the measurement method of the present disclosure is more accurate than the thickness value determined only by using the output signal of the eddy current sensor 20.

[0040] Figure 3 FIG. 3 shows a flowchart of a measurement method 300 for the thickness of a metal film of a wafer according to an embodiment of the present disclosure.

[0041] As shown in Figure 3 FIG. 3, measurement method 300 includes:

[0042] Step 310, determine a first mapping relationship between the thickness of the metal film of the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is a preset standard height, wherein the coefficient in the first mapping relationship is related to the resolution of the eddy current sensor 20;

[0043] Step 320: Determine the second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20;

[0044] Step 330: Modify the coefficients in the first mapping relationship according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is the target lift-off height; and

[0045] Step 340: Based on the target output signal, determine the thickness of the metal thin film of the wafer to be detected according to the third mapping relationship.

[0046] In step 310, the preset standard height can be the lift-off height at which the eddy current sensor 20 has the best detection effect, and the magnitude of the above standard height is related to the specific model and parameters of the measuring instrument 100. In some embodiments, the first mapping relationship can be determined in advance and stored in the relevant memory of the measuring instrument 100. When calculating the thickness, this first mapping relationship can be retrieved from the memory. In some other embodiments, the first mapping relationship can also be determined before measuring the thickness of the metal thin film of the wafer to be detected. For example, the first mapping relationship can be fitted by obtaining the output signals of the eddy current sensor 20 corresponding to multiple metal thin film samples with different and known thicknesses. The first mapping relationship can be expressed as:

[0047] T = f(x) (1)

[0048] Wherein, T represents the thickness of the metal thin film, and x is the output signal of the eddy current sensor 20. In some embodiments, f(x) can be a cubic function, that is,

[0049] T = Ax 3 + Bx 2 + Cx + D (2)

[0050] Wherein, A, B, and C are the coefficients in the first mapping relationship, and these coefficients are directly related to the resolution of the eddy current sensor 20. Those skilled in the art can understand that the resolution of the eddy current sensor 20 is defined as the change rate of the measured value (i.e., the magnitude of the output signal of the eddy current sensor 20) with the change in the thickness of the metal thin film. Whenever the thickness of the metal thin film changes by a unit thickness, if the change amplitude of the output signal of the eddy current sensor 20 is larger, it indicates that its resolution is larger; otherwise, the resolution is smaller. Therefore, according to the above definition, the coefficients A, B, and C in formula (2) are related to the resolution of the eddy current sensor 20.

[0051] As described above, the lift-off height will affect the resolution of the eddy current sensor 20. Therefore, there is a second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20. Generally speaking, the higher the lift-off height, the smaller the resolution of the eddy current sensor 20. In step 320, similar to the first mapping relationship, the second mapping relationship can be pre-determined and stored in the relevant memory of the measuring instrument 100. When calculating the thickness, this second mapping relationship can be retrieved from the memory. In some other embodiments, the second mapping relationship can also be determined before measuring the thickness of the metal film of the wafer to be detected. For example, the above second mapping relationship can be determined by obtaining the output signals of the eddy current sensor 20 corresponding to metal films with different known thicknesses at different lift-off heights. The second mapping relationship can be expressed as:

[0052] K = g(h) (3)

[0053] where K represents the resolution of the eddy current sensor 20, and h represents the lift-off height. Moreover, the coefficients A, B, and C in Equation (2) are related to K.

[0054] In step 330, the coefficients A, B, and C in Equation (2) will be corrected according to Equation (3). Specifically, h = h1 (where h1 represents the target lift-off height) can be substituted into Equation (3), so as to calculate the target resolution K1 of the eddy current sensor 20 at the position of the target lift-off height. Subsequently, the target resolution K1 is used to correct the coefficients A, B, and C in Equation (2) to obtain the corrected coefficients A1, B1, and C1. Finally, a third mapping relationship between the thickness of the metal film of the wafer and the output signal of the eddy current sensor 20 at the position of the target lift-off height is obtained. The third mapping relationship can be expressed as:

[0055] T = A1x 3 +B1x 2 +C1x + D (4)

[0056] In step 340, by substituting the value of the target output signal obtained in the previous step into Equation (4), the thickness value of the metal film of the wafer can be calculated.

[0057] It should be noted that although in this embodiment, f(x) is shown in the form of a cubic function, it can be understood that f(x) can also be other function forms such as a linear function or a quadratic function. Similarly, g(h) can also be various function forms such as a linear function or a quadratic function. The embodiments of the present disclosure do not limit the specific function forms of f(x) or g(h). In addition, when f(x) is in other function forms, the number of coefficients to be corrected included therein will also be different. For example, in some examples, the number of coefficients to be corrected can be one or two, and in other examples, the number of coefficients to be corrected can be more than three.

[0058] Figure 4 FIG. 4 shows a flowchart of a method 400 for determining a first mapping relationship according to an embodiment of the present disclosure. As Figure 4 shown, the method 400 includes:

[0059] Step 410, when the eddy current sensor 20 is adjusted to a position at a standard height, the eddy current sensor 20 is used to detect a plurality of sample wafers in the sample wafer set respectively, so as to obtain output signals of the eddy current sensor 20 corresponding to each sample wafer in the plurality of sample wafers, wherein the upper surface of each sample wafer included in the sample wafer set is covered with a metal thin film having different and known thicknesses; and

[0060] Step 420, fitting a first mapping relationship according to the thickness of each sample wafer in the plurality of sample wafers and the output signal of the eddy current sensor 20 corresponding to the sample wafer.

[0061] In the method of this embodiment, a sample wafer set prepared in advance can be used to determine the first mapping relationship. The sample wafer set includes a plurality of sample wafers, for example, 5, 6, 8, or 10 sample wafers. These sample wafers can have wafer bodies of the same size, but the metal thin films covered on the upper surfaces of the wafers are different, and the metal thin films of these wafers have different thickness values. Specifically, these sample wafers can have metal thin films with gradually increasing thicknesses.

[0062] Before performing the method of this embodiment, first use the distance adjustment device 11 of the measuring instrument 100 to adjust the lift height to a position at a standard height, and the above adjustment can be completed by observing the reading of the distance measuring sensor 50. In step 410, a plurality of sample wafers in the sample wafer set can be sequentially placed on the carrier plate 30, and then when each sample wafer is placed on the carrier plate 30, the output signal of the eddy current sensor 20 is acquired. Finally, a series of data of the thicknesses of the metal thin films and the corresponding output signals are obtained.

[0063] Table 1 shows the relevant data of a plurality of sample wafers included in a set of sample wafer sets according to an embodiment of the present disclosure.

[0064] Sample Wafer Number Thickness / nm Output Signal 1 72.6 145.6 2 146 335.5 3 208.5 475.8 4 303.1 598.4 5 382 711.8 6 559.5 818.1

[0065] Table 1

[0066] In step 420, to establish the relationship between the output signal of the eddy current sensor 20 and the thickness of the metal thin film of the sample wafer, a fitting method can be used to determine the above first mapping relationship. The fitting methods include, but are not limited to, piecewise linear fitting, least squares fitting and other methods.

[0067] The method of this embodiment can use the set of sample wafers to determine the first mapping relationship on site. Compared with determining the first mapping relationship in advance and storing it in the memory, the first mapping relationship calculated by using the method of this embodiment will be more accurate. This is because there may be individual differences among different measuring instruments 100. Using the pre-determined first mapping relationship cannot accurately reflect the relevant working parameters of the actually operated measuring instrument 100, while the first mapping relationship determined on site can accurately reflect the above relevant working parameters, so that the thickness of the metal thin film calculated subsequently is more accurate.

[0068] Figure 5 shows a flowchart of a method 500 for determining a second mapping relationship according to an embodiment of the present disclosure. As Figure 5 shown, the method 500 includes:

[0069] Step 510, adjusting the eddy current sensor 20 to the position of each sample height in turn;

[0070] Step 520, at the position of each sample height, determining the resolution corresponding to the eddy current sensor 20, wherein step 520 further includes:

[0071] Step 521, using the eddy current sensor 20 to detect each sample wafer in the set of sample wafers to obtain the output signal of the eddy current sensor 20 corresponding to each sample wafer at the position of this sample height; and

[0072] Step 522, determining the resolution of the eddy current sensor 20 at this sample height according to the thickness of each sample wafer in the set of sample wafers and the output signal of the eddy current sensor 20 corresponding to each sample wafer at this sample height; and

[0073] Step 530, determining the second mapping relationship according to the multiple sample heights and the resolution of the eddy current sensor 20 corresponding to each of the multiple sample heights.

[0074] The multiple sample heights can be pre - determined lift - off heights. These sample heights can, for example, be in the form of an arithmetic progression, that is, the adjacent two sample heights have the same height difference. In step 510, the distance adjustment device 11 of the measuring instrument 100 can be used to adjust the lift - off height to the position of a certain sample height, and the above - mentioned adjustment can be completed by observing the reading of the ranging sensor 50.

[0075] In step 521, at any sample height, a plurality of sample wafers in the above - mentioned set of sample wafers are sequentially placed on the carrier plate 30, and then when each sample wafer is placed on the carrier plate 30, the output signal of the eddy current sensor 20 is acquired. Finally, a series of data on the thickness of the metal thin film and the corresponding output signals is obtained.

[0076] Finally, a series of data on the thickness of the metal thin film and the corresponding output signals is obtained. The data of the output signals corresponding to each sample wafer is similar to the data shown in Table 1, but due to different lift - off heights, the output signals corresponding to each sample wafer are not the same as the output signals shown in Table 1.

[0077] In step 522, the resolution of the eddy current sensor 20 at the position of this sample height can be directly calculated through the data obtained in step 521.

[0078] To simplify the description, assume that the first mapping relationship T = f(x) is in the form of a linear function, that is, T = Cx. Then the resolution of the eddy current sensor 20 (or the coefficient in the first mapping relationship) can be directly calculated using the data of two sample wafers with different metal thin film thicknesses. Specifically, the thickness difference of the metal thin films of these two sample wafers and the signal difference of the output signals corresponding to these two sample wafers can be calculated respectively, and then dividing the thickness difference by the signal difference can obtain the resolution of the eddy current sensor 20 at this sample height. It can be understood that in some embodiments, the first mapping relationship T = f(x) can be a more complex function form. In this case, more data of sample wafers may be required to calculate the resolution of the eddy current sensor 20, and the specific calculation method is determined according to the function form of f(x), which will not be elaborated here.

[0079] After determining the resolution of the eddy current sensor 20 at each sample height in step 520, in step 530, the functional relationship between the resolution of the eddy current sensor 20 and the lift - off height, that is, the second mapping relationship, can be determined by means of fitting and the like.

[0080] In some other embodiments, the above - mentioned second mapping relationship can also be determined by using the curve relationship diagram of different lift - off heights and the corresponding sensor output signals. Figure 6Shows a curve relationship diagram of the lift-off height and the corresponding sensor output signal obtained for a sample wafer according to an embodiment of the present disclosure. In Figure 6 , the relationship between the output signal y and the lift-off height x can be expressed as a quadratic curve y = -1.197088x 2 +4.250079x + 0.163580. Using the method described above, for a certain sample wafer, multiple sets of data of the output signals corresponding to the sample wafer at different sample heights can be obtained, and these data are further used to fit a curve as Figure 6 shown. Finally, based on multiple different sample wafers, multiple curves as Figure 6 shown can be obtained. Subsequently, based on these curves, the relationship between the resolution and the lift-off height can be determined, that is, the above-mentioned second mapping relationship.

[0081] The following provides an implementation manner for determining the first mapping relationship and the second mapping relationship and performing actual metal thin film thickness measurement.

[0082] Establish the first mapping relationship of the eddy current sensor 20 and perform fitting on the first mapping relationship. The fitting method can adopt the piecewise linear fitting, least squares fitting, etc. described above. The above-mentioned first mapping relationship can be expressed by a polynomial equation as

[0083] T = A0 + A1x 1 + A2x 2 + ··· + A n x n (5)

[0084] The above formula can be expressed as T = f(x), where T is the measured sample thickness, x is the output signal value of the eddy current sensor 20, and A0…A n are coefficients related to the resolution of the eddy current sensor 20.

[0085] By calibrating the same set of sample wafers with different thicknesses at different lift-off heights H0, H1…H n , the relationship model between the output of the eddy current sensor 20, the lift-off height H, and the sample thickness T can be obtained. This relationship model can be expressed as a matrix, that is,

[0086]

[0087] T0, T1…T n respectively represent the measured sensor output values of the eddy current sensor 20 at different lift-off heights H0, H1…H n , and the calculated thickness obtained through calculation for the same sample wafer. Its value should be as close as possible to the actual thickness T of the sample. The above formula (6) actually includes the second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20.

[0088] Assume that with the lift-off height H as the reference, a set of lift-off heights is set with a step size of λ. For example, each lift-off height is set at H - nλ, …, H - λ, H, H + λ, …, H + nλ, and marked as H -n 、H0…H n 。Calibration is performed using the same set of samples with different thicknesses to obtain the relationship model between the output of the eddy current sensor 20, the lift-off height H, and the sample thickness T. Each coefficient A in the above formula (6) is obtained 00 …A nn After that, the measurement of the actual thickness of the metal thin film can be carried out.

[0089] When the measurement starts, the ranging sensor 50 real-time feeds back the actual lift-off height h when measuring each point. The processor of the measuring instrument 100 determines that h is within the range of, where H y = H + yλ, and determines the characteristic curve at this time according to the above formula (6): T com = A y0 + A y1 x 1 + A y2 x 2 + ··· + A yn x n , and the eddy current sensor 20 calculates the thickness of the measured sample according to this characteristic curve.

[0090] Return to Figure 1 , the measuring instrument 100 further includes a driving component configured to drive the eddy current sensor 20 and the ranging sensor 50 to move relative to the carrier plate 30. The driving component may include: a swing arm 10 and a rotating device 40. The eddy current sensor 20 and the ranging sensor 50 are fixed to the swing arm 10, and the swing arm 10 is configured to drive the eddy current sensor 20 and the ranging sensor 50 to move along a direction parallel to the diameter direction of the carrier plate 30, that is, along Figure 1 the X direction shown. The rotating device 40 is connected to the carrier plate 30 and is configured to drive the carrier plate 30 to rotate. As Figure 1 shown, the rotating device 40 will drive the carrier plate 30 to rotate along the direction indicated by the arrow. Both the swing arm 10 and the rotating device 40 can be realized by motors (for example: stepper motors and rotating motors). By combining the translational movement of the swing arm 10 and the distance adjusting device 11 and the rotation of the rotating device 40, the eddy current sensor 20 and the ranging sensor 50 can be set at any position in the space above the carrier plate 30.

[0091] Figure 7 shows a flowchart of a method 700 for obtaining a target output signal and a target lift-off height according to an embodiment of the present disclosure. As Figure 7As shown, the method 700 includes:

[0092] Step 710, using a driving device to move the eddy current sensor 20 and the ranging sensor 50 to a plurality of positions to be measured relative to the wafer to be detected along a preset path; and

[0093] Step 720, at each of the plurality of positions to be measured, respectively obtaining the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50, so as to determine the thickness of the metal thin film of the wafer to be detected at each of the plurality of positions to be measured.

[0094] Since the thickness of the metal thin film of the wafer is not uniform, or rather, the metal thin film may have different thicknesses at different positions, when measuring the thickness, the positions where the wafer needs to be measured for thickness are first determined. In some embodiments, in order to be able to detect the overall topography of the metal thin film of the wafer, the thickness of the metal thin film at a plurality of different positions can be measured in sequence, and then the overall thickness situation of the metal thin film can be deduced or simulated by using relevant calculation software. In step 710, the eddy current sensor 20 and the ranging sensor 50 can be moved to a plurality of positions to be measured relative to the wafer to be detected along a preset path. In step 720, at each position to be measured, the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50 are respectively obtained, so as to obtain a set of relevant data for a plurality of positions to be measured. Subsequently, the thickness of the metal thin film at the position to be measured can be calculated according to the relevant data of each position to be measured.

[0095] In some embodiments, the above preset path includes: a straight line path that coincides with the diameter of the wafer to be detected on a horizontal plane; and / or a circular path centered on the center of the wafer to be detected on a horizontal plane. Figure 8 The figure shows a schematic diagram of a preset path according to an embodiment of the present disclosure. Figure 8 The solid line in the figure represents the edge of the wafer, and the dashed line represents a possible preset path. Figure 8Two preset paths are shown. Among them, path a coincides with the diameter of the wafer to be detected. When the preset path selects path a, the rotating device 40 can remain stationary, and only the swing arm 10 drives the eddy current sensor 20 and the distance measuring sensor 50 to move above the carrier plate 30 along the diameter direction of the carrier plate 30. In this case, the measuring instrument 100 can measure the relevant data of multiple positions to be measured on the diameter of the wafer. Path b coincides with a certain concentric circle of the wafer to be detected. When the preset path selects path b, the swing arm 10 can remain stationary, and only the rotating device 40 drives the carrier plate 30 to rotate. In this case, the measuring instrument 100 can measure the relevant data of multiple positions to be measured on the concentric circle of the wafer. In some other embodiments, the preset path can also be other more complex movement paths, and the positions to be measured are multiple points on this movement path. It can be understood that no matter what shape the preset path is, the eddy current sensor 20 and the distance measuring sensor 50 can be controlled to move along this path by controlling the driving component.

[0096] In some embodiments, the measuring instrument 100 further includes an in-situ sensor 60. The in-situ sensor 60 is configured to detect the position of the notch of the wafer to be detected during the process of the rotating device 40 driving the carrier plate 30 to rotate. Figure 9 A longitudinal sectional view of the measuring instrument 100 according to an embodiment of the present disclosure is shown. The position of the in-situ sensor 60 is set to be aligned with the notch of the wafer in the radial direction of the wafer, so as to be able to detect the notch of the wafer. As Figure 9 shown, the in-situ sensor 60 can be a transmissive in-situ sensor 60. The transmissive in-situ sensor 60 has a transmitting end and a receiving end. The transmitting end emits red light or infrared light, and the receiving end is used to receive the light emitted by the transmitting end. When the wafer exists between the transmitting end and the receiving end, the light transmission is cut off, and the receiving end cannot receive the optical signal; while when the notch of the wafer passes between the above two, the receiving end can receive the optical signal, and at this time the in-situ sensor 60 outputs a detection signal. Therefore, when the wafer rotates to the position where its notch reaches the in-situ sensor 60, the trigger switch of the in-situ sensor 60 is triggered. The relevant processor of the measuring instrument 100 is configured to: determine the current rotation position of the wafer to be detected according to the detection result of the in-situ sensor for the notch, so as to facilitate setting the driving component to drive the eddy current sensor 20 and the distance measuring sensor 50 to move along the preset path. Exemplarily, during the rotation of the wafer, the relevant processor can record the rotation angle of the carrier plate 30 within a certain time period, so that the current rotation position of the wafer can be determined according to the moment when the in-situ sensor detects the notch and the rotation angle of the carrier plate 30 after this moment. Subsequently, referring to the rotation positions of the wafer at various moments, combined with the rotation of the carrier plate 30 and the radial movement of the swing arm 10, the eddy current sensor 20 and the wafer can be made to move relative to each other along the above preset path.

[0097] In some embodiments, for the edge measurement of the metal thin film on the wafer, an edge compensation algorithm is used to correct the data. The eddy current measurement generates an eddy current magnetic field, which exists in a certain area on the surface of the metal thin film. Therefore, the finally measured thickness value is essentially the average thickness of a certain area on the surface of the metal thin film that generates the eddy current effect. In addition, during the process of the sensor magnetic field projection completely entering the wafer, there is a situation where part of the magnetic field projects outside the wafer, so there is a certain magnetic field attenuation, resulting in measurement deviation at the wafer edge position. On the other hand, according to the measured data, when comparing the eddy current measurement data with the metal thin film thickness model of the actual wafer, there is a certain shrinkage phenomenon. An edge attenuation model is established based on the measured data, and within the threshold distance range from the edge, a certain correction is made to the measured film thickness information. The above threshold distance range can be, for example, 5 mm, 10 mm, 15 mm, etc.

[0098] The above correction includes: correcting the coordinates of the position to be measured; and / or correcting the thickness measurement value corresponding to the position to be measured. For example, the coordinate information of the position to be measured corresponding to the measured thickness can be pre-corrected, and (r, θ, T) is corrected to (r + Δr, θ, T), where r and θ are the coordinates of the position to be measured in the polar coordinate system, and T is the measured thickness; or a compensation correction is made to the measured value obtained at the position to be measured, and (r, θ, T) is corrected to (r, θ, T + ΔT).

[0099] Figure 10 A schematic diagram showing the 2D graphical display of the thickness of the metal thin film of the wafer to be detected is shown, where Figure 10 the abscissa represents the radial coordinate r of the position to be measured, and the ordinate represents the thickness measurement value of the position to be measured. In some embodiments, the above correction of the coordinates of the position to be measured includes: for each position to be measured: keeping the thickness measurement value corresponding to the position to be measured unchanged, and increasing the coordinate value of the position to be measured, where the increase amount of the coordinate value of the position to be measured close to the edge of the wafer to be detected is greater than the increase amount of the coordinate value of the position to be measured far from the edge of the wafer to be detected. Specifically, as Figure 10 shown, curve 1 represents the thickness measurement value of the metal thin film obtained by contact measurement such as four-probe measurement. Since contact measurement is adopted, this curve 1 is close to the true value of the metal thin film thickness; curve 2 represents the thickness measurement value measured by the method of the present disclosure but without edge compensation; curve 3 represents the thickness measurement value measured by the method of the present disclosure and with edge compensation. In this embodiment, the radial coordinates of each position to be measured are compensated, that is, the data (r, θ, T) of each position to be measured is corrected to (r + Δr, θ, T). This compensation can be understood as stretching curve 2 in the Figure 10 direction of the abscissa to obtain curve 3.

[0100] In some other embodiments, the above-mentioned correction of the thickness measurement value corresponding to the position to be measured includes: for each position to be measured: keeping the coordinates of the position to be measured unchanged, increasing the thickness measurement value corresponding to the position to be measured, wherein the increase amount of the thickness measurement value of the position to be measured close to the edge of the wafer to be detected is greater than the increase amount of the thickness measurement value of the position to be measured far from the edge of the wafer to be detected. Continuing to refer to Figure 10 As shown, in these embodiments, the radial coordinates of each position to be measured are compensated, that is, the data (r, θ, T) of each position to be measured is corrected to (r, θ, T+ΔT). This compensation can be understood as lifting the edge part of curve 2 in Figure 10 the direction of the ordinate to obtain curve 3.

[0101] Although in the above embodiments, two different correction methods are described separately, in some other embodiments, these two correction methods can also be used simultaneously, that is, coordinate correction and thickness measurement value correction are performed simultaneously. As Figure 10 shown, the corrected curve 3 is closer to the true curve (i.e., curve 1) than the uncorrected curve 2.

[0102] After measuring the thickness of the metal thin film at multiple positions to be measured, the thickness of the metal thin film at each position of the wafer can be calculated or deduced, and then data such as the average thickness, maximum value, minimum value, and standard deviation of the metal thin film within the statistical radius of the wafer can be calculated and displayed in 2D or 3D graphics. Figure 11 Shows a schematic diagram of 3D graphical display of the thickness of the metal thin film of the wafer to be detected.

[0103] According to another aspect of the present disclosure, there is also provided a measuring instrument 100 for the thickness of the metal thin film of a wafer, including: a carrier plate 30 for carrying the wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor 20 disposed above the carrier plate 30, configured to use the eddy current effect to excite an eddy current magnetic field in the metal thin film of the wafer and detect the intensity of the eddy current magnetic field to generate a corresponding output signal; a ranging sensor 50 disposed above the carrier plate 30 for measuring the lift-off height of the eddy current sensor 20 from the wafer; and a processor communicatively connected to the eddy current sensor 20 and the ranging sensor 50, configured to respectively obtain the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50 when the carrier plate 30 carries the wafer to be detected; and determine the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height. The processor of the measuring instrument 100 can be communicatively connected to other components of the measuring instrument 100 for controlling these components or obtaining the data generated by these components. For the description of each component in the measuring instrument 100, refer to Figure 1 the description, which will not be elaborated here.

[0104] In some embodiments, the above-mentioned processor is further configured to: determine a first mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is a preset standard height, wherein the coefficient in the first mapping relationship is related to the resolution of the eddy current sensor 20; determine a second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20; correct the coefficient in the first mapping relationship according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is the target lift-off height; and determine the thickness of the metal thin film of the wafer to be detected based on the third mapping relationship according to the target output signal.

[0105] In some embodiments, the above-mentioned processor is further configured to: when the eddy current sensor 20 is adjusted to a position at the standard height, use the eddy current sensor 20 to detect a plurality of sample wafers in the sample wafer set respectively to obtain the output signal of the eddy current sensor 20 corresponding to each sample wafer in the plurality of sample wafers, wherein the upper surface of each sample wafer included in the sample wafer set is covered with a metal thin film having different and known thicknesses; and fit the first mapping relationship according to the thickness of each sample wafer in the plurality of sample wafers and the output signal of the eddy current sensor 20 corresponding to the sample wafer.

[0106] In some embodiments, the above-mentioned processor is further configured to: adjust the eddy current sensor 20 to the position of each sample height in turn, and at the position of each sample height: use the eddy current sensor 20 to detect each sample wafer in the sample wafer set to obtain the output signal of the eddy current sensor 20 corresponding to each sample wafer at the position of the sample height; and determine the resolution of the eddy current sensor 20 at the position of the sample height according to the thickness of each sample wafer in the sample wafer set and the output signal of the eddy current sensor 20 corresponding to each sample wafer at the position of the sample height; and determine the second mapping relationship according to the plurality of sample heights and the resolution of the eddy current sensor 20 corresponding to each sample height in the plurality of sample heights.

[0107] In some embodiments, the gauge 100 further includes: a driving component configured to drive the eddy current sensor 20 and the ranging sensor 50 to move relative to the carrier plate 30, wherein the processor is further configured to: use the driving component to move the eddy current sensor 20 and the ranging sensor 50 to a plurality of positions to be measured along a preset path relative to the wafer to be detected; and at each of the plurality of positions to be measured, respectively obtain the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50, so as to determine the thickness of the metal thin film of the wafer to be detected at each of the plurality of positions to be measured.

[0108] According to one aspect of the present disclosure, there is provided an electronic device, which includes a memory, a processor, and a computer program stored on the memory. The processor is configured to execute the computer program to implement the steps of any of the above-described method embodiments.

[0109] According to one aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-described method embodiments are implemented.

[0110] According to one aspect of the present disclosure, there is provided a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of any of the above-described method embodiments are implemented.

[0111] In the following, in conjunction with Figure 12 descriptive examples of such electronic devices, non-transitory computer-readable storage media, and computer program products are described.

[0112] Figure 12 An example configuration of an electronic device 1200 that can be used to implement the methods described herein is shown. For example, the above-described gauge 120 for measuring the thickness of a wafer metal thin film may include an architecture similar to that of the electronic device 1200, or may be wholly or at least partially implemented by the electronic device 1200 or a similar device or system.

[0113] The electronic device 1200 may include at least one processor 1202, a memory 1204, (multiple) communication interfaces 1206, a display device 1208, other input / output (I / O) devices 1210, and one or more mass storage devices 1212 that can communicate with each other, such as via a system bus 1214 or other suitable connections.

[0114] The processor 1202 can be a single processing unit or multiple processing units, and all processing units can include a single or multiple computing units or multiple cores. The processor 1202 can be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operation instructions. Among other capabilities, the processor 1202 can be configured to obtain and execute computer-readable instructions stored in the memory 1204, the mass storage device 1212, or other computer-readable media, such as the program code of the operating system 1216, the program code of the application 1218, the program code of other programs 1220, etc.

[0115] The memory 1204 and the mass storage device 1212 are examples of computer-readable storage media for storing instructions that are executed by the processor 1202 to implement the various functions described above. For example, the memory 1204 generally can include both volatile and non-volatile memories (e.g., RAM, ROM, etc.). In addition, the mass storage device 1212 generally can include a hard disk drive, a solid-state drive, removable media, including external and removable drives, memory cards, flash memory, floppy disks, optical disks (e.g., CD, DVD), storage arrays, network-attached storage, storage area networks, etc. The memory 1204 and the mass storage device 1212 can both be collectively referred to as memory or computer-readable storage media in this document, and can be non-transitory media capable of storing computer-readable, processor-executable program instructions as computer program code that can be executed by the processor 1202 as a specific machine configured to implement the operations and functions described in the examples herein.

[0116] Multiple programs can be stored on the mass storage device 1212. These programs include the operating system 1216, one or more applications 1218, other programs 1220, and program data 1222, and they can be loaded into the memory 1204 for execution. Examples of such applications or program modules can include, for example, computer program logic (e.g., computer program code or instructions) for implementing the following components / functions: Method 120 to Method 600 (including any suitable steps of the methods), and / or additional embodiments described herein.

[0117] Although in Figure 12is illustrated as being stored in the memory 1204 of the electronic device 1200, but the modules 1216, 1218, 1220, and 1222 or portions thereof can be implemented using any form of computer-readable medium accessible by the electronic device 1200. As used herein, "computer-readable medium" includes at least two types of computer-readable media, namely computer-readable storage media and communication media.

[0118] Computer-readable storage media includes volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVDs), or other optical storage devices, magnetic cassettes, magnetic tapes, magnetic disk storage devices or other magnetic storage devices, or any other non-transitory media that can be used to store information for access by an electronic device. In contrast, communication media can embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism. Computer-readable storage media as defined herein does not include communication media.

[0119] One or more communication interfaces 1206 are used to exchange data with other devices, such as via a network, direct connection, etc. Such communication interfaces can be one or more of the following: any type of network interface (e.g., network interface card (NIC)), wired or wireless (such as IEEE 802.11 wireless LAN (WLAN)) wireless interface, Worldwide Interoperability for Microwave Access (WiMAX) interface, Ethernet interface, Universal Serial Bus (USB) interface, cellular network interface, Bluetooth TM interface, Near Field Communication (NFC) interface, etc. The communication interface 1206 can facilitate communication within a variety of network and protocol types, including wired networks (e.g., LAN, cable, etc.) and wireless networks (e.g., WLAN, cellular, satellite, etc.), the Internet, etc. The communication interface 1206 can also provide communication with external storage devices (not shown) such as in storage arrays, network-attached storage, storage area networks, etc.

[0120] In some examples, a display device 1208, such as a monitor, can be included for displaying information and images to a user. Other I / O devices 1210 can be devices that receive various inputs from a user and provide various outputs to the user, and can include touch input devices, gesture input devices, cameras, keyboards, remote controls, mice, printers, audio input / output devices, etc.

[0121] The techniques described herein can be supported by these various configurations of the electronic device 1200 and are not limited to the specific examples of the techniques described herein. For example, the functionality can also be implemented in whole or in part on a "cloud" using a distributed system. The cloud comprises and / or represents a platform for resources. The platform abstracts the underlying functionality of the hardware (e.g., servers) and software resources of the cloud. Resources can include applications and / or data that can be used when performing computing processing on servers remote from the electronic device 1200. The resources can also include services provided over the Internet and / or over a subscriber network such as a cellular or Wi-Fi network. The platform can abstract the resources and functionality to connect the electronic device 1200 with other electronic devices. Thus, the implementation of the functionality described herein can be distributed throughout the cloud. For example, the functionality can be implemented in part on the electronic device 1200 and in part through a platform that abstracts the functionality of the cloud.

[0122] The foregoing description is only a preferred embodiment of the present disclosure and an illustration of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A method for measuring the thickness of a metal thin film on a wafer, wherein, The described measurement method is used for a measuring instrument for measuring the thickness of a metal thin film on a wafer. The measuring instrument includes: a carrier plate for carrying the wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier plate and configured to use the eddy current effect to excite an eddy current magnetic field in the metal thin film of the wafer and detect the intensity of the eddy current magnetic field to generate a corresponding output signal; and a ranging sensor disposed above the carrier plate for measuring the lift-off height of the eddy current sensor from the wafer; a driving assembly configured to drive the eddy current sensor and the ranging sensor to move relative to the carrier plate. The measurement method includes: When the carrier plate carries the wafer to be detected, driving the eddy current sensor and the ranging sensor to move relative to the carrier plate, and respectively obtaining the target output signal generated by the eddy current sensor and the target lift-off height measured by the ranging sensor; and Determining the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height.

2. The measuring method according to claim 1, wherein, Determining the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height includes: Determining a first mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor when the lift-off height measured by the ranging sensor is a preset standard height, wherein the coefficient in the first mapping relationship is related to the resolution of the eddy current sensor; Determining a second mapping relationship between the lift-off height and the resolution of the eddy current sensor; Correcting the coefficient in the first mapping relationship according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor when the lift-off height measured by the ranging sensor is the target lift-off height; and Determining the thickness of the metal thin film of the wafer to be detected based on the third mapping relationship according to the target output signal.

3. The measuring method according to claim 2, wherein, Determining a first mapping relationship between the thickness of the metal thin film of the wafer and the output signal of the eddy current sensor when the lift-off height measured by the ranging sensor is a preset standard height includes: After the eddy current sensor is adjusted to the position of the standard height, using the eddy current sensor to detect a plurality of sample wafers in a sample wafer set respectively to obtain the output signal of the eddy current sensor corresponding to each sample wafer in the plurality of sample wafers, wherein the upper surface of each sample wafer included in the sample wafer set is covered with a metal thin film with different and known thicknesses; and Fitting the first mapping relationship according to the thickness of each sample wafer in the plurality of sample wafers and the output signal of the eddy current sensor corresponding to the sample wafer.

4. The measuring method according to claim 3, wherein, Determining a second mapping relationship between the lift-off height and the resolution of the eddy current sensor includes: Adjusting the eddy current sensor to the position of each sample height in a plurality of sample heights in turn. At the position of each sample height: Detect each sample wafer in the sample wafer set using the eddy current sensor to obtain the output signal of the eddy current sensor corresponding to each sample wafer at the position of the sample height; and Determine the resolution of the eddy current sensor at the sample height according to the thickness of each sample wafer in the sample wafer set and the output signal of the eddy current sensor corresponding to each sample wafer at the sample height; and Determine the second mapping relationship according to the plurality of sample heights and the resolution of the eddy current sensor corresponding to each of the plurality of sample heights.

5. The measuring method according to any one of claims 1-4, wherein, When the carrier plate carries the wafer to be detected, respectively obtaining the target output signal generated by the eddy current sensor and the target lift-off height measured by the distance measuring sensor further includes: Using the driving device to move the eddy current sensor and the distance measuring sensor to a plurality of positions to be measured relative to the wafer to be detected along a preset path; and At each position to be measured among the plurality of positions to be measured, respectively obtain the target output signal generated by the eddy current sensor and the target lift-off height measured by the distance measuring sensor, so as to determine the thickness of the metal thin film of the wafer to be detected at each position to be measured among the plurality of positions to be measured.

6. The measuring method according to claim 5, further comprising: Perform data correction on a plurality of positions to be measured and the corresponding measured thicknesses, wherein the plurality of positions to be measured include a plurality of positions whose distances from the edge of the wafer to be detected are within a threshold distance range, and the data correction includes: Correct the coordinates of the position to be measured; and / or Correct the thickness measurement value corresponding to the position to be measured.

7. The measuring method according to claim 6, wherein, Correcting the coordinates of the position to be measured includes: For each position to be measured: keep the thickness measurement value corresponding to the position to be measured unchanged, and increase the coordinate value of the position to be measured, wherein the increase amount of the coordinate value of the position to be measured close to the edge of the wafer to be detected is greater than the increase amount of the coordinate value of the position to be measured far from the edge of the wafer to be detected.

8. The measuring method according to claim 6, wherein, Correcting the thickness measurement value corresponding to the position to be measured includes: For each position to be measured: keep the coordinates of the position to be measured unchanged, and increase the thickness measurement value corresponding to the position to be measured, wherein the increase amount of the thickness measurement value of the position to be measured close to the edge of the wafer to be detected is greater than the increase amount of the thickness measurement value of the position to be measured far from the edge of the wafer to be detected.

9. A measuring instrument for the thickness of a metal thin film on a wafer, comprising: A carrier plate for carrying a wafer, wherein the upper surface of the wafer is covered with a metal thin film; An eddy current sensor is arranged above the carrier plate and configured to excite an eddy current magnetic field in the metal thin film of the wafer by using the eddy current effect and detect the intensity of the eddy current magnetic field to generate a corresponding output signal; A distance measuring sensor is arranged above the carrier plate for measuring the lift-off height of the eddy current sensor from the wafer; A driving component configured to drive the eddy current sensor and the distance measuring sensor to move relative to the carrier plate; and A processor, communicatively connected to the eddy current sensor, the ranging sensor, and the driving assembly, configured to drive the eddy current sensor and the ranging sensor to move relative to the carrier plate when the carrier plate carries the wafer to be detected, respectively obtain a target output signal generated by the eddy current sensor and a target lift-off height measured by the ranging sensor; and determine the thickness of the metal thin film of the wafer to be detected according to the target output signal and the target lift-off height.

10. An electronic device, comprising: At least one processor; And At least one memory, storing a computer program thereon, Wherein, when the computer program is executed by the at least one processor, the at least one processor is caused to execute the measurement method according to any one of claims 1 to 8.

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